Advisor(s)
Abstract(s)
Peach stones were used as raw material for the synthesis of activated carbons with different properties. Firstly,
peach stones were chemically activated using a 12M H3PO4 solution and carbonized under flowing air (400 °C).
The obtained activated carbon, named as PS, is characterized by a high surface development
(SBET=1262m2 g−1) and acidic character (pHPZC=4.2). A fraction of PS was further carbonized under N2
atmosphere at 800 °C to remove surface functionalities and to increase its basicity (PS-800). In addition, a Pt
catalyst supported on PS (3% w/w Pt/PS) was synthesized by incipient wetness impregnation, resulting in a
considerable hydrophilicity increasing. The synthesized materials were tested in the catalytic wet peroxide
oxidation (CWPO) of highly concentrated solutions of 4-nitrophenol (4-NP, 5 g L−1) during 24 h experiments,
conducted at relatively mild operating conditions (T=50–110 °C, pH=3, catalyst load=2.5 g L−1 and
[H2O2]0=17.8 g L−1, corresponding to the stoichiometric amount of H2O2 needed for the complete mineralization
of 4-NP). It was observed that the increase of electron-donating functionalities in PS-800 promotes the
generation of reactive HO% radicals, being the activity towards CWPO twice higher than that obtained with the
pristine PS. Besides, increasing operating temperature substantially enhances CWPO, finding a 80% of 4-NP
removal at 110 °C. On the other hand, despite the sharp increment in H2O2 decomposition due to the presence of
Pt particles in Pt/PS catalyst, this decomposition is inefficient in all cases, with a consequent poor pollutant
removal. This can be attributed to the recombination of HO% radicals into non-reactive species −scavenging
effects, promoted by the hydrophilicity of the catalyst.
Description
Keywords
Activated carbon Chemical activation Metal-free CWPO Peach stone
Citation
Martin-Martinez, Maria; Álvarez-Torrellas, Silvia; García, Juan; Silva, Adrián M.T.; Faria, Joaquim L.; Gomes, Helder T. (2018). Exploring the activity of chemical-activated carbons synthesized from peach stones as metal-free catalysts for wet peroxide oxidation. Catalysis Today. ISSN 0920-5861. 313, p. 20-25